The invention is an improvement on the ion chip of U.S. Pat. No. 7,161,789 B2 issued Jul. 9, 2007 to instant applicant, which teaches an ionising structure physically mounted on and in electrical contact with a metallic surface of the ion chip. One pole of a high voltage generator is connected to the metallic surface to provide a high voltage. The ionising structure emits a stream of ions generated by corona discharge from one or more ionising electrodes, while the metallic surface provides an electrostatic repulsing field which directs the ion stream outward. Generally there are insulating walls projecting outward near the ionising structure forming a channel construction to protect it. Although the ionising structure can generate both positive and negative ions, in general for air cleaning, conditioning, freshening and purifying negatively charged atmospheric ions are generated.
Negatively charged atmospheric ions have two primary effects in air cleaning, conditioning, freshening and purifying. One is the introduction of negative ions to change the ionic balance of the incoming ventilating air, which of itself is considered beneficial. In fact the metal ducts of modern air conditioning systems act as ground removing negatively charged ions from the air leaving positively charged ions. The second is to precipitate particulate matter from the air, most contaminants are particulate in nature, thus cleaning or purifying the air. In hospitals the particulate matter includes bacteria, As it is thought much iatrogenic (hospital generated) disease is caused by airborne bacteria, reducing particulate matter should reduce iatrogenic infection. Both effects are important when air is recycled or recirculated in buildings. The emitters can also be used to provide an ionic barrier across a doorway or corridor to reduce particulate matter, thus bacteria levels and so any resulting infection.